Sewing machine



Filed Oct. 12, 1946.

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'7 Sheets-Sheet 7 Filed Oct. 12, 1946 atenten Jan. 17, 1950 SEWING MACHINE Charles F. Rubel, Chicago, Ill., assignor to Union Special Machine Company, Chicago, Ill., a corporation of Illinois i Application October 12, 1946, Serial No. 702,928

13 Claims. (Cl. 112-162) The present inventionV relates to improvements in looper thread handling mechanism for an overedge sewing machine, of which the stitch forming devices include a movablev eye needle, an under looper and an overedge looper which cooperate to form a series of locked loop stitches passing from one side to the other o the work around the edge thereof. f

While machines of the general type referred to are readily adaptable for the forming of a number of different stitches with one, two, or three threads, the present invention is concerned only with the organization of such a machine adapted for the formation of stitches with two or three threads and which is provided with either one or two thread carrying lcopers.

, It is a principal objectof the invention to provide a novel construction and arrangement of the looper thread handling devices in an overedge sewing machine of the general type described, which will providefor the more emcient and accurate control of a looper thread or threads under the most severe conditions of high speed operation to insure the formation of tight,` well-formed stitches, and without excessive straining or breakage of thread.

It is another object of the invention to provide a simplified and improved form of thread handling mechanism for a thread carrying looper in which the motions of the moving parts of another looper mechanism are utilized and combined with the movements of the thread carrying looper for the taking up and control of the looper thread.

It is a further object of the invention to provide in an overedge sewing machineof this general description, a novel and improved arrangement of the overedge looper thread handling mechanism in which a thread guide moving with the under looper arm'acts in combination with the overedge looper and suitable xed guiding means on the machine to control and to take up the overedge looper thread. l

It is another object .of the invention to provide in an overedge sewing machineof this description, a novel andimproved arrangement of the under looper thread vhandling mechanism in which the desired take-up action is imparted to the under looper thread through the cooperative action of thread guides associated with certain moving parts of the overedge looper mechanism with relation to the under looper and with relation to associated fixed guiding means on the machine. Y It is another object of the invention to provide an improved means for the adjustment of the position of the overedge looper in accordance with the size of needle, which will permit such adjustment to be made without disturbance of related adjustments of the several operating parts of the overedge looper mechanism. y

With these and other objects in view as may hereinafter appear, a feature of the invention consists in the construction and arrangement of the thread guiding means through which thread is supplied to a thread carrying under looper, said means including guides associated with the overedge looper lever, its more upwardly disposed supporting arm, and the stud to which said arm is secured to provide a more eicient and accurate take-up and control of the thread supplied to a thread carrying under'looper. Specically, in accordance with the invention, two adjacent thread eyes are provided in the overedge looper lever and in the upper supporting arm therefor respectively, and cooperate with two relatively stationary guides on the machine to take up theV under looper thread during movement of the overedge looper from its raised overedge position in which the guides and thread eyes are in substantial alignment, to a position of maximum take-up when the overedge looper reaches the limit of its downward or retracting movement. The twoadjacent thread eyes referred to, supported respectively on the overedge looper and on the supporting arm, are arranged to move away from their position of alignment as the overedge looper is retracted and their separation is the result of the movement of the parts about two different pivot points. Moreover, another eyelet, carried by the same stud which carries the upper supporting arm mentioned, is rocked in relation to other fixed guides to impart a further take-up action to the under looper thread.V The net result is to eifect a differential take-up of the under looper thread, the timing and extent of which is determined in part by the rocking movement of the upper stud with the extra eyelet and the supporting arm for the overedge looper and in part by the movement of the overedge looper itself. The arrangement of these thread eyes and cooperating stationary thread guides is such as to provide a maximum take-up of the under looper thread at those points in the operating cycle at which the overedge looper reaches each limit of its movement. The timing of the overedge looper mechanism, including the thread guiding means above referred to, with relation to the movements of the under looper is such as to cause tension to be applied to the under looper thread first during the upward movement of the under looper to tighten the previous stitch and to draw thread from the supply,

and edge trimming mechanisms are particularly illustrated and described in the patent to Christensen, et al. above noted, and form specically no part of the present invention, no detailed disclosure or description thereof is made herein. The needle 42 is secured to a needle bar 58 which reciprocates in a xed sleeve bearing 60. The needle bar 58 is connected to be driven from the shaft 38 by means of a crank 62 mounted on the forward end of the shaft and a connecting link 64 connected at its upper end with a block 66 on the needle bar 58.

The under looper 44 illustrated in the drawings (Figs. 3, 5, 7, 9, 11, and 13) as being of the thread carrying variety, is attached by screws 68 to a carrier arm rigidly secured to the forward end of a stud 12 which is rotatably mounted in an axially adjustable sleeve bushing 14 in a wall 16 of the machine base l0. The stud 12 and under looper 44 are arranged to have imparted thereto an oscillatory movement from an eccentric 18 (Figs. 3 and 15) on the drive shaft 38, through connections which include an eccentric strap 80 and a pitman 82 which is connected at itslower 'end to a ball stud 83 (Figs. 4 and 15) on one arm f of a rock member 84 supported on a shaft 86. A forked link 88 connects the free end of a downwardly extending arm 85 of member 84 with an upwardly extending arm 90 secured to the rocker stud 12. 'A forked member 92 secured to the lower end of the pitman 82 is arranged to straddle an extension 94 of the arm of member 84 in order to prevent undue vibration of the parts. The toggle action provided by member 84 and link 88 tends to produce a substantial dwell in the movement of the under looper at the limit of its retracting stroke and a relatively rapid movement of the looper during its loop-seizing and retracting movements.

The overedge looper arm 46 (Figs. 7, 9, and 11), or the spreader 45 (Figs. 1, 2, and 8), as shown in the drawings, is supported intermediate its length by a short link or arm 96 carried on a stud 98, and is supported at its lower end ona supporting arm |00 carried on a stud |02, to the inner end of which is secured a lever arm |04 (Fig. 4). The lever arm |04 is connected by a ball stud |06 with a strap at the lower end of a pitman |08. A strap ||0 at the upperend of the pitman cooperates with an eccentric ||2 on the drive shaft 31. The arrangement of the rock shaft |02, stud 98, and supporting links |00, 86 is such as to cause the overedge looper 46 iirst to be moved upwardlyv over the edge of the fabric, and then to be swung about its pivotal connection ||4 with the supporting arm 96 in a counterclockwise direction as viewed in Fig. 1 to position its loop of thread for engagement by the descending needle. In the illustrated form of the invention, an improved arrangement of the supporting and actuating mechanism for the overedge looper 46 is provided, which will permit of a simple and easy adjustment of the looper in accordance with dif.-

ferent sizes of needle without disturbing the relation between the looper and its supporting and actuating means, thus also eliminating danger of binding of the parts. VTo this end, la supporting block ||6 is provided which has formed therein journal bearings for the studs 98 and |02, and which is in turn mounted for adjustment forwardly and rearwardly of the machine in a guideway indicated at ||8 (Figs. 1 and 4) formed in a bracket |20 rigidly secured to the machine frame.

The supporting block ||6 is secured in adjusted` position to the bracket |20 by means of a c1amp lng screw |22 which extendsthrough a horizon tally'disposed slot in the bracket |20, and is screwthreaded into the block I6.

The present machine is equipped for the supply `of three threads which include a needle thread |30, an overedge looper thread |50 and an under looper thread |32 (Fig. 5). The thread take-up and control devices through which the needle thread is supplied to the needle include a thread tension |33 with thread guides |34, |36 lthrough whichthe thread is drawn, a stationary thread eye |38 (Fig. 2) and an elongated thread eye |40 (Fig. l) formed in a needle thread take-up arm |42.. carried by .the needle actuating link 64. The thread passes through the eye |40 to a thread eye |44 carried on a fixed bracket |46, and then downwardly along the outside of the machine cas- Iing to the needle 42. The thread take-up and control devices through .which the overedge looper thread |is supplied to the thread carrying overedge looper 46 include a thread tensioning device |52 and associated thread eyes |54, |56 mounted on the right side of the machine, a fixed thread guide |58 (Fig. 5), and a thread take-up arm |60 which is supported to move with the under looper 44. The overedge looper thread |50 passes from the tensioning device |52 and thread eye |56 to an eye in the fixed thread guide |58, thence downwardly to the thread take-up arm |60, back through a second thread eye in the fixed thread guide |58, and then `to the overedge looper 46. l

' The thread take-up and control devices through which the under looper thread |32 is supplied to -the thread carryingrunder looper 44 include a. thread tension |64 and associated thread guides (Fig. 2) mounted on the right side of the machine, and a thread tube |10 which carries the thread transversely across the casing to the rear of the looper operating mechanism. A thread guide |12 (Figs. 3 and 4) mounted on a vertical bracket |14 and formed with transversely extend,- ing portions providing three aligned eyelets, carries the .thread forwardly in cooperative relation with an interposed thread take-up in the form of a thread eye |18 (Figs. 3, 6, and 8) offset from but secured to theupper supporting stud 98for the overedge looper arm 46. .The thread then passes through a thread eye in a stationary arm |88'iormed in a bracket |82 secured by a clamping screw |84 to the supporting block |28, thence to a second take-up'device which comprises a thread eye |86 formed in an upward extension of the link 96 and a thread eye |88 forming an upward extension of the overedge looper lever 46.. `Thread |32 passes from the thread eye |88 through a thread eye in another stationary arm |901Lof the bracket |82 and then to the under looper 44.

The Athread eye |18 referred to, comprises a wire member adjustably secured by set screws |92 in" a block .|94 offset from a disc member |96 which is adjustably secured, by means of a set `screw |98, on the stud 98 (Fig. 16). The thread eye |18 is thus adapted for adjustment radially, axially andangularly with relation to the stud 98, permitting an accurate adjustment of both the timing and extent of its thread take-up action. The operation of the sewing and thread handling devices o'f the machine, including the needle and :under and overedge loopers, and more particularly the operation of the under and overedge Vlooper thread take-up devices for the formation of a three-thread overedge stitch, will be described linfconnection with vthe series of diagrammatic views 'v-Figs. -5 -to 14) -.inclusive of the drawings, of which Figs.5' andfshomthe:sevcralfioperating parts in position at the. beginning .fof the-stitch forming cycle. .The '.needleLA 42 .isafat'ithis ftime" in its .-lowermost workfpiercingmosition,'awhile Athe movement of the .overedge slooper,I which rin ;t,urn

advances to engage `thereontthesloopxof nnder looper thread and tto; presenty -a sloop -.of .overedge :looperthreadlto -theneedlewhilethe underlooper moves .downwardly :as Vindicated in -Fig. '2li-.1. Finally, the overedgezlooperxstarts itseretracting movement, as .shown .fFig. '13, the needle proceeds -downwardly .fand @the .under looper lis returned vto .its :fully retracted. -position. In Ethis sequence of operations, .the under looper.:is.re .tained in its ffullyfretra'cted:position-.through-a substantial .dwell period .by the .operation of zits toggle driving connection, as `indicated by :the transition .from Fig. 13 tosfFig. :5, and :is then caused to be advanced .fand .retracted atxa'rela- .tively ira-pid :rate einy :order 'itogprovide 'f f or :the-:most f :effective cooperation of .these vseveral .thread -handling devices.

'Thesoperation ofthe threadacontrolsanddiake-.up devices 'for vthe overedge .looper-.is l.briefly asrfollows-:Starting with the position shownfrin rFig. i5., in which the ;overedge looper is Aapproaching'its .retracted position, :the under-looper:remainsffully retracted and .the .associated ,take-'upzlarm -fs r-.at .the limit of itszmovement-ftoward the'zxedthread arm, .the overedgedooper `thread11511.15 :free :fof tension. the under looper :now :moves :uprwardlyancl theoveredge looperfreachesthe-,lower .end of its movement, the:overedge looper l.threa'c'l placed 'iunder-` some itension by the :continued clockwise "movement -zof threadv arm |160 :anw-.by ff the movement of .the looper .itself 2 (-see Fig. 7). Thereafter, as 1the foveredge -looper #moves upwardly'and laterallyrst toseize the vloop rif-:under looper thread (see Fig. 9) @and thereafterinto ,position to have its loopfenteredbyi-therdown-v \wardly .moving needle, .the 'overedge looperthrea'd .1|i50 is heldfunder a1.vsubstantial1tension whichs `maintained' until the overedgefflooper reaches':-its

maximum high position (see Fig. 11). Themen fsion on the overedgezlooper threadis-relieved as the Overedge Alooper .begins zits,.-retracting -move- Iment, and the needle athen, .uponits-downwand movement, passes ,through the #loop which ffis .formed -in yoveredgeilooperthread. The foveredge looper thread"remainsloose'fduringrthefretracting stroke of the Aoveredge looper through :theiposi- Ytions illustratedinfliigs. -.1-3.-'and15.

The thread control J-and Ltake-.up@devices for `the under looper thread are constructcdandsarfrangedto produce a .condition-oftensiorrupon.the Ff yunder `looper thread .during :a 'portion of -.the :upward movement of the .under :looper :lever 'which coincides vwith-'the movement 4of -theroveredge looper `t0 its ifnlly'retracted position, and

`toagain Vtension the-thread duringfaiportion .fof '375 Athe @downward movement of .the under -'looper whichl coincides l with .the movement Y of. Vthe overedge ylooper vtoits extreme .advanced overedge position. Thev tensioning .of the .under vlooper thread.takes,place Vduring the earlypartof ythe upward movementofithe under looper as vit enters the -needlerloopas showninrFig. 7. The v tension on. the --under vlooperthread is yagain slackedoi as .the Aunder looper reaches the limit of its advancing movement ,andstartsto return, .thus facilitating Lthe :movement of the ,overedge looper through the under looper ythread loop. .The under-.looper thread isl again tensionedduring a port-ion :of 'lthe freturn movement .of the under looper .to ,the position shown vlparticularly `in Fig. 11,:in order to cause .the loop .of under looper .threa'dlzto 'be :drawn: firmly .against the overedge looper, andithereaftertofbe fully taken in toset the :.stitc-h. 'The .tension ion rthe yunder looper thready iszagainlslacked pT-:as-the under looper reaches its fully .retracted position shown in Eig. `13.

1F01q :the `fullyiretractecl position-.of .the loveredgeilooper, amaximum1take-up .fof the under v4looper threadis obtained as shown in Fig. 7, by the movementrof thefthreadeyes'lS, |88 out of alignmentwith each other .and with the..xed thread vguides |80, |90 '(see Fig. 4). For vthis position of the parts, anadditionaltakeeup .of the under looper thread .is obtained by movementxof .the thread eye |18 somezdistancetovthe .right ofits in-linezposition with relationfto the stationary thread fguideflTZ :asshown inFig. v8. For thefully advancedsposition of 'the overedge looper v(see Fig. ,11),t acondition vof .maximum ltake-upto tightenitheunder looper: thread'is obtained "by the movement of the rearwardly fdisposedithread eye :|18 to'itsrextreme positionito the left as showniniFig. :1-2. '.For .this .position .of .the'-.overe'dge looper, the vthread eyes |86, |88 :areinssubstantial alignment with'the stationary .thread `guides |80, |90, sothat the amount of .thread taken .up is controlled entirely'by the -ad'justment'of the thread eye y| 18.

"Thezdiierential movement of .the'ithread .eyes 5F86, |88 .with relation to .the :xed guides |80, .4.920, and withrelation' to leyelet |18 `servesfto vprovide an additional factor of control of the vfunderlooper threadwhich causes the take-up ac- A:tion to conform precisely'with the movements of :the underlooper 44. It'fwill be notedthat as the pveredge looper'is retracted from its fully adivance'd position, lshownin Fig. 11, in'which the 'threadieyes |86, |88 .are in .alignment with the stationary thread .guides v|80, |90, the thread veyesare moved out of alignment with the xed gui-'deafandare at thev same time lgradually differentiated with relation to onea'nother, this *movement continuing v.with la corresponding increase the take-up action-uponthe under'looper thread =until the overedge looper vrllt reaches its ffullyrretracte'd vposition 'of Fig? 7. .'Byv appropriate'- 4lyforming'orlocating'the projections ofthe looper lever-M l and 'armi 961and the thread guiding apertures therein'and .byrproper adjustment offeye- 'let'fl `18, it ris, possi-ble toprovide a' veryaccurately :controlled take-up action for the vunder looper .thread at .the criticalipoints ofthecycle.

Figs. land 16 of the drawings, illustratea ..differentsetup of'the sewing instrumentalities'in `which the overedge vlooper memberfli which has lbecnfsubstituted -for the `.thread v carrying looper V46,:is of thespreader type. With'this set-up fof the sewing mechanism, a two-thread .over- .edgestitch .is .-formed'with-a needle thread and a an underlooper thread. It is the function of the overedge looper to engage and carry the descending needle. 'Ihe movements imparted to the overedge looper spreader 45 are, however, identical with those imparted .to the thread carrying overedge looper 46, so that the operation of the control and take-up devices for the under looper thread remains unchanged.

Features of construction of the machine which relate to the lubrication of the main drive shaft 38, the eccentrics, and eccentric straps driven therefrom as shown generally in Fig. 3 of the drawings, form the subject matter of an application for Letters Patent now pending in the United States Patent Office, and are, therefore, not here particularly described and claimed.

While an illustrative form of the invention has been described in considerable detail, it willbe understood that numerous changes in the construction and arrangement of the several parts and in the general application of the invention may be made, Without departing from its principles and scope. The terms and expresf sions used herein have been employed as terms of description and not 'of limitation.

What is claimed is:

1. In an overedge sewing machine, a needle, an under looper mechanism having oscillatory partsincluding a thread carrying under looper, an overedge looper mechanism having oscillatory parts including an overedge looper, means for actuating said needle and looper mechanisms in timed relation to form ra'stitch,`and thread take-F up devices associated with said thread carrying under looper consisting solely of stationary thread guides,V and a plurality of movable guiding means supported from the oscillatory parts of said overedge looper mechanism and guiding means onf'i said under looper arranged to engage said thread at progressive points in its path in such manner that the relative movements of said overedge looper mechanism and' of said under looper .are eiective to take up the thread.

2. In an overedge sewing machine, a needle, an under looper mechanism having oscillatory parts including a thread carrying under looper, an overedge looper` mechanism having oscillatory :parts including an 'overedge looper, actuating means for oscillating said needle and loopers between advanced and retracted positions timed to move the overedge looper to a fully retracted position when the under looper is advancing and`4 to a fully advanced position 'when the' under@ looper is retracting, and thread take-up devices for said under looper consisting of stationary thread guides, a plurality of movable guides supported from oscillatory parts of the overedge looper mechanism including at least one guide carried by the overedge looperV itself, and a guide on the under looper, said guides being arranged in such a manner as to effect a maximum take-up of thev thread at each limit of movement of the overedge looper, one of said movable guides being ladjustable to vary its take-up effect. 'v 1' 43. In'an overedge sewing machine, a needle, an under looper'mechanismincluding a thread carrying under looper, an overedge looper mechanism including 'an overedge looper, a supporting stud and an arm therefrom pivotally connected with said overedge looper intermediate its length, actuating means for imparting oscillatory move-V ments to said needle and loopers between advanced and retracted positions'in timed relation to form a stitch, including an actuating connection with the overedge looper, thread take-up devices for the under looper thread including adjacently disposed thread guides on said arm and ,on said overedge looper, and stationary thread guides cooperating therewith from which the thread passes to the under looper, said movable thread guides being arranged for a diiierential movement away from said stationary guides as the overedge looper is retracted to effect a maximum take-up of the under looper thread for the fully retracted position of the overedge looper.

4. In an overedge sewing machine, a needle, an under looper mechanism including a thread carrying under looper, an overedge looper mechanism including an overedge looper, a supporting stud and an arm therefrom pivotally connected with said overedge looper intermediate its length, actuating means for imparting oscillatory movements to said needle and loopers between advanced and retracted positions in timed relation to form a stitch including an actuating connection timed to move the overedge looper to its retracted position while the under looper is advancing and to its advanced position While the under looper is retracting, thread take-up devices Vfor said under looperv thread consisting of an -thread guides on said arm and on said overedge looper, and stationary thread guides cooperating therewith to effect a maximum take-up of said under looper thread for the fully retracted position of the overedge looper.

5. In an overedge sewing machine, a needle, an under looper mechanism including a thread carrying underlooper, an overedge looper mechanismV including an overedge looper, an upper supporting stud and an arm therefrom pivotally connected with said overedge looper intermediate its length, a lower supporting stud and an arm therefrom pivotally connected with said overedge looper, means for imparting' oscillatory movements to said needle and loopers between advanced and retracted positions in timed relation to form a stitch, including a connection for oscillating saidlower stud, and under looper thread take-up devices comprising a take-up thread guide oiiset on said upper supporting stud with .cooperating stationary thread guides at opposite sides thereof, and take-up thread guides adjacent one another on said upper arm and overedge looper with cooperating stationary thread guides at opposite sides thereof from which the thread passes to the under looper.

6. In an overedge sewing machine,a needle, an under looper mechanism including a thread car- -rying underlooper, anoveredge looper mechanism including an overedge looper, an `upper supporting stud 'and an arm therefrom pivotally connected with said overedge looper intermediate its length; a lower supporting stud and an arm therefrom pivotally connected with said voveredge looper, means for imparting oscillatory movements to -said needle andloopers between advanced and retractedpositions timed to move -the overedge looper to a fully retracted position when the under looper is advancing, and to a fully advanced position when the under looper is re- ".tracting, and thread 'take-up` devices for said under looperV thread" consisting of a take-up 13 means for securing the block in adjusted position, and under looper thread take-up devices consisting of a take-up thread guide offset on said upper stud, and stationary thread guides cooperating therewith to eieot a maximum take-up of the under looper thread at the limit of the advancing movement of the overedge looper, differentially movable thread take-up guides on said upper arm and overedge looper, and cooperating thread guides fixed on said block at opposite sides of said differentially movable thread guides arranged to eiect a maximum take-up of said un der looper thread for the fully retracted position of the overedge looper.

CHARLES F. RUBEL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Date Knaus sept. 29, 1942 

